SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cb76625bb046ecf7a486d60d912963d0296b09b8817544e0aea1baeb0a22bef' 
  AND token = 'ecmWggj1OeH9G2v0Msv+Fjp+thri8W5yyKBia9WIfYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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