SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c90eaf3cabcd7dda694502f54f0cc5cd7db9ae58fcd6dd918c3dc6109d84372e' 
  AND token = 'qFRdP82s2X9dAgKeeBKliAWHUu1Ba/hbqqS9e+7KTT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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