SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03e8cc2d820a58b2c35eeeaaf99fd8c578ae751e68c575746d5424a075239569' 
  AND token = 'ZcbVOfUMAXcCllCrUlDW9oQR2DBqE3PtlsEsK+k6zGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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