SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7bf813e71918ec2fec135c5711dc26f2e31d2ca7f140ccf9a5cfafbda420558' 
  AND token = 'in0F1RD56ri9EMPu2NalvjdFBQFXfwY5b3/oXQyzjQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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