SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30ebbdbe331aa70c0beaf338d68297f401559aea390d1ffe2b67f7cedbe7d58e' 
  AND token = 'UALYdFqxhXDeBmoS4HvJUlV7Gfr4ct20ZwFmuj+Fw0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}