SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '940563c144b90d57c39f66cf4306979e4a61319bd769c2a22fddd87946caa234' 
  AND token = 'G839dVrADQpcOJD9+Ghs6iuh7r4nA/cNNkpNLTrtqYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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