SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0f698974ec402efc1079eecbfaae5afdc691e34f243ab01c748911f92fe05e2' 
  AND token = 'QKdxJu6+bcEvI5Qd+qpfVKgoFanAjMqDAQicDt+80gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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