SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e50eb6360c14f0292b2152dc53f76cf6ff956349731dfeb790a6d2a0b2c6758b' 
  AND token = 'UlH1z0GAXK+Z3XzRZG5SKqWh2lDfghiNb6M3URgYGvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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