SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58fb47a83b2c68d0acc60788ace46311cda9268a12585dfb02a17ddbbf203478' 
  AND token = 'lKfBfMXsiOeuj9tsWrE0iXOPG3ga7BQaVCztA3aWPrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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