SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9da6819a52235b11ba7c82eb2dd65994cff24e0b15c0fd427dfa8a34dafbfa9' 
  AND token = 'FnLA1vHdOEG3oEPv+zaEDaWVmoRqCkdAq+EeB8kij5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}