SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f7a6bbe824e0492ca12826a218aaed639ced713a265723a7c994138209ef937' 
  AND token = 'jG+UTi8JbGBWFBEoC3qaUDWjG5p4OzzWKI/+hkj3GQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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