SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37cbef2bc346dd7d702bbe4502d64175b3805e01ceca1f624ed3bdf2e8c4f877' 
  AND token = 'TND4tYuolTpXHkgj40ut/PprsmySJ+kbaFpYwzaI/Us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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