SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23e5cca56b351358c2237e61d4c5eb783da14df829f724662e773d41124e097c' 
  AND token = 'Pvr/pcrUCyvxojeYlLWLFitwrHMlmdwF/ZI9udN0FVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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