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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe35d77c5c1adccc1a0b451283aea7a6e3d2e02b39772129d0bd2492b1963a2' 
  AND token = 'pryCYZdjBIjDvXFPw3mZx3cZ+N/TrUtY5SLZCB/z9MM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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