SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c728a4ff1e5004ebc52702369dd27ead811fb47c93974b45cdc9df5569410c75' 
  AND token = 'qBopjjIDNt6+cHBiD4dVAVFCGIjLq07/4ZXmG+aiNqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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