SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd77f6b333dd05ac1d3072d8cc73b80c5e29d551fd1da089ee3d2ef68721fd1a3' 
  AND token = 'CzXyxWT7EqBDbUA3lsVtRotp3BlRzmk/2IV66cKb8Tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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