SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2bb3372e920a9b883f2d74bd535c4c72fc7f5772731c6613e7b26322b10e34b' 
  AND token = '8B+vPvFnrK3j/gXV6bRP8lmTSWbJ6c15U7zEzhjaI50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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