SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ca9032c13540cdfea837bad5362f5cf2373ad5b10ef1f9b054cd7f856501397' 
  AND token = 'PMUX6IgLh8+YY1MZs0hNEs7IRJd50ORHeVBieiYrga8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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