SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1fafb8bd903a62a61421a4caa7eb8946c1a0b3055da919e1cd5a39b4286b6e3' 
  AND token = 'lCFkqyJdAjVHeuzyuGhDWJIqcMSzNeov5NHbNOKh/2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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