SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f904acec6d2e0344b8a720abd899b997f91a66337e4831f2d96cdfaf5b378e2' 
  AND token = 'gJAneO3/5cUs9hMXuGX0Is4+usmgv/BzFs6LCv4cCmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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