SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c1925761796e54524628fe5da85d563560a269cdba5d2acc7396d9e6a87ea635' 
  AND token = 'XXGta7P7izyNH09PTkqBysIFTmfAin99kVAHNekDHC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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