SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8842bc08957a691e2655ce26e5dcc6aa1a561a65ea1cc4f44ff42be713e989b' 
  AND token = 'QYFS9rcCLTukRaYb+IlFxbuMUZsbe+kVGUvG/R2pjQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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