SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fac9d1aff0e309522a74dfb9326262d8b02c158f206f649bdd538922c3a569d' 
  AND token = 'Il7qpzLjhSfL3bea451RCXM+gYXgl6ijeAcXAis11qM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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