SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bb527e6491f2b5d70897321f40f011fac9fda42b8d62f30c379dc2f20add1e7' 
  AND token = 'pBuD/7wAxUUzM4HcsQuhSWlX/1BIsY4UAgZ4Ry0eIAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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