SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4784886e6011244c4a7c4e791f17aabbdee068bbde0843212c7b092a6a42ad0a' 
  AND token = 'PGi2m31CKg8ok6we1TltnDW2+DIf1O3rsTlxWgyGyyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables